1. Field of the Invention
The invention relates, to a process for producing folded products, a product stream being split up into at least two sub-streams which, once the products have undergone a final folding operation, are reunited, and the reunited product stream being observed and, following the detection of products with inaccuracies stemming from the folding operation carried out following the splitting-up action, adjustment of the relevant folding arrangement taking place. The invention relates further to a folder which has a diverter for splitting up a product stream into a plurality of sub-streams which each contain at least one adjustable folding arrangement, preferably designed as a longitudinal-folding arrangement, and which can be fed to a common delivery arrangement.
2. Description of the Related Art
The splitting up of the product stream in the folder usually takes place before the so-called quarter fold is produced. The reason for this is that a folding arrangement for achieving a quarter fold usually allows a considerably smaller throughput than the printing machine provided upstream of the folder, with the result that, if use is made of just one folding arrangement for producing the said fold, it would not be possible for the capacity of the printing machine to be fully utilized. Up until now, however, it has no longer been possible, once the sub-streams have been reunited, to assign the individual products to the different sub-streams. If, during observation of the reunited product stream, products with inaccuracies in the quarter fold are detected, it has not been possible, up until now, to carry out a quick, specific adjustment of the relevant folding arrangement. Rather, up until now, tests have had to be conducted to find out which folding arrangement is involved. It is only when the relevant folding arrangement has been established that adjustment is possible. According to experience, this results in a high number of inaccurately folded and thus low-quality or completely unusable products being produced.
The object of the present invention is to improve a process and a folder of the type mentioned above using straightforward and cost-effective means, such that, upon detection of products with inaccuracies stemming from the folding operation carried out following the splitting-up action, specific correction is permitted and the number of rejects produced is thus kept as small as possible.
This object is achieved according to the invention in that, taking the process of the generic type as the departure point, at least in the case of detection of products with inaccuracies stemming from the folding operation carried out following the splitting-up action, the products of at least one sub-stream are marked at least for a short time before the sub-streams are reunited. For this purpose, in a folder of the type mentioned above at least one sub-stream is assigned a marking arrangement for marking the products passing in it.
The process of the invention involves splitting a feeding stream of products into at least two product sub-streams. Each sub-stream is then passed through an associated final folding unit with the final folded sub-streams being united into a common products stream at a delivery station downstream of the folding units. The products of the common stream are monitored to detect any final folding inaccuracies therein. On detection of a product folding inaccuracy, products of at least one of the sub-streams are marked following final folding but before reuniting the sub-streams. This enables the sub-stream containing the marked products to be identified in the common stream from the products of the other sub-stream. Adjustment of the folding unit associated with the identified sub-stream then can be made to eliminate the inaccuracy causing condition.
These measures completely eliminate the disadvantages outlined in the introduction. The marking of the products advantageously makes it possible for said products to be assigned to the individual sub-streams. On account of the products being assigned reliably to the individual sub-streams, the corrections which are necessary in the case of folding inaccuracies can be carried out in a specific manner with a 100% success rate. This means that the period of time required for eliminating defects is shortened to a not inconsiderable extent in comparison with the prior art, as a result of which the number of rejects produced in this time is reduced considerably in comparison with the prior art. The measures according to the invention thus give a high level of user-friendliness and result overall in excellent cost-effectiveness.
The invention also provides a folder for producing folded products which includes a diverter for splitting a stream of feeding products into at least two sub-streams. Separate adjustable folding units associated with each of the sub-streams longitudinally fold the products in the respective sub-streams. The sub-streams thereafter pass downstream to a common delivery station. A marking unit is disposed proximal a travel course of at least one of the sub-streams for marking products in that sub-stream.
By a monitoring at the common delivery station, this marking is employed to identify the sub-stream from whence come any inaccurately folded products and, accordingly, adjusting the folding unit associated with the sub-stream to eliminate the cause of inaccuracies is effected.
It is expediently possible for the marking to be provided only on a product region or part of a product which can be removed during subsequent processing of the product. This means that the products remain saleable as long as the folding defect does not render the products market unacceptable.
A further advantageous measure may consist in that, in order to mark the products, a marking means which is visible or can be made visible is applied to said products. Such a means may advantageously be sprayed on or jetted on, which allows a contact-free application which does not have any adverse effects. In particular in the case of a jetting-type application, a high level of target accuracy is also advantageously ensured.
A particularly expedient development of the generic folder may consist in that a switching arrangement for actuating the marking arrangement is arranged in the region of the common delivery arrangement. This ensures that, upon detection of folding inaccuracies, a printer who is observing the product stream on the common delivery arrangement can actuate the marking arrangement according to the invention manually for a short time. Even after just a short period of time, the marked products appear on the common delivery arrangement, as a result of which it is possible to assign the products to the individual sub-streams, and thus also to assign the defective products to the relevant folding arrangements.
The marking arrangement may advantageously be arranged in the region between the folding arrangement of the associated sub-stream and the common delivery arrangement. This ensures that the products running past the marking arrangement are marked on their outside, with the result that the marking can also easily be seen in the region of the common delivery arrangement.
For the customary action of splitting up into two sub-streams, it is sufficient if the products of only one sub-stream are marked. This makes it possible to keep the necessary outlay within limits and to achieve good distinguishability.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.